Make value range analysis tolerate erroneous length expressions.

Make value range analysis tolerate erroneous length expressions.

BUG= http://dartbug.com/21166
R=floitsch@google.com

Committed: https://code.google.com/p/dart/source/detail?r=43836

[herhut, 2015-02-18 10:22:04]

herhut@google.com changed reviewers:
+ floitsch@google.com, zarah@google.com

[herhut, 2015-02-18 10:24:35]

This fixed the symptom and solves the problem for this optimisation. 

What I really think would help is to make the various containsOnlyXXX helpers
return true for empty types (as they contain nothing, and thus nothings else
besides XXX). This would have made the given code tolerate the bug in the input
program, as well. However, such a change would be very far reaching.

[floitsch, 2015-02-18 11:55:21]

LGTM, but add a test, since we want to fix the co19 tests.

[herhut, 2015-02-18 12:11:02]

New patchsets have been uploaded after l-g-t-m from floitsch@google.com

[herhut, 2015-02-18 12:12:04]

Committed patchset #2 (id:20001) manually as 43836 (presubmit successful).

[floitsch, 2015-02-18 13:52:48]

Still LGTM.

https://codereview.chromium.org/936483004/diff/20001/tests/compiler/dart2js_e...
File tests/compiler/dart2js_extra/21166_test.dart (right):

https://codereview.chromium.org/936483004/diff/20001/tests/compiler/dart2js_e...
tests/compiler/dart2js_extra/21166_test.dart:1: // Copyright (c) 2015, the Dart
project authors.  Please see the AUTHORS file
I prefer if it is in the language tests.

Give the test a "correct" name, and mention the bug only in the comments (as you
do now).

https://codereview.chromium.org/936483004/diff/20001/tests/compiler/dart2js_e...
tests/compiler/dart2js_extra/21166_test.dart:6: // Fails when compiling with
--checked.
Shouldn't fail.

https://codereview.chromium.org/936483004/diff/20001/tests/compiler/dart2js_e...
tests/compiler/dart2js_extra/21166_test.dart:21: doStuff(); // This is expected
to fail but not crash the compiler.
Check your operations.

https://codereview.chromium.org/936483004/diff/20001/tests/compiler/dart2js_e...
tests/compiler/dart2js_extra/21166_test.dart:22: } catch (_) {}
Make sure this is a TypeError.